Halophenoxy benzamide herbicides

ABSTRACT

1. AN HERBICIDAL COMPOUND HAVING THE FORMULA:   1-(O2N-),2-(R-CO-),4-((X)N-PHENYLENE-O-)BENZENE   WHEREIN X IS A HALOGEN, N IS 1 TO 5, AND R IS AMIDO, ALKYLAMIDO (C1-C6), OR DIALKYLAMIDO (C1-C6).

United States Patent O R 7 Claims ABSTRACT OF THE DISCLOSURE 2-Nitro-5-(halophenoxy)benzoic acids and esters, salts, amides, and acyl halides thereof comprise a class of compounds that are highly effective preand post-emergence herbicides.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of copending application Ser. No. 194,481, filed Nov. 1, 1971, now abandoned, Which is a division of application Ser. No. 819,412, filed Apr. 25, 1969, now US. Pat. No. 3,652,645.

BACKGROUND OF THE INVENTION Field of the Invention This invention is concerned with certain phenoxybenzoic acid compounds and their use as herbicides.

DESCRIPTION OF THE PRIOR ART It has been proposed to use as herbicides 2-methoxybenzoic acids (U.S. 3,013,054) and 4-phenoxybenzoic acids (French 1,502,538). It is the discovery of this invention, however, that benzoic acids having a phenoxy substituent in the 5-position are very effective herbicides.

SUMMARY OF THE INVENTION This invention provides herbicidal compound having the formula C O R wherein X is halogen, n is 1 to 5, and R is amido, alkylamido (C -C preferably C -C or dialkylamido (C -C preferably C -C DESCRIPTION OF SPECIFIC EMBODIMENTS 2-nitro-5-(2',4',6-trichlorophenoxy) benzoic acid; methyl 2-nitro-5-(2,4,6-trichlorophenoxy)benzoate; propyl 2-nitro-5-(2',4,6-trib1omophenoxy)benzoate; phenyl 2-nitro-5- 2',4,5 '-triflu0rophenoxy benzoate; 2-nitro-5- 2',4',6-triiodophenoxy) benzoic acid; 2-nitro 5- 2',4',6'-trichlorophenoxy benzoyl chloride; 2-nitro-5-(2,4,6'-trichlorophenoxy)benzamide; N-ethyl 2-nitro-5-(2',4',6-trichlorophenoxy)benzamide;

3,839,444 Patented Oct. 1, 1974 ice N-isopropyl 2-nitro-5-(2',4',6'-trich1orophenoxy) benzamide;

N,N-dimethyl 2-nitro-5- (2,4,6'-trichlorophenoxy) benzamide;

sodium (or potassium) 2-nitro-5-(2',4',6'-trichlorophenoxy) benzoate;

ethylammonium 2-nitro-5-(2',4,6-trichlorophenoxy) benzoate;

ethanolammonium 2-nitro-5-(2',4',6-trichlorophenoxy) benzoate;

sodium 2-nitro-5-(2',4',6-trichlorophenoxy)benzoate;

methyl 2-nitro-5-(2',4,5'-trichlorophenoxy)benzoate;

methyl 2-nitro-5-(2',4-dichlorophenoxy)benzoate; and

methyl 2-nitro-5-(2',3,4,5,6'-pentachlorophenoxy) benzoate.

The following example illustrates the preparation of a typical compound of this invention and demonstrates a method for product recovery.

EXAMPLE 1 Methyl 2-nitro-5- (2',4,6'-trichlorophenoxy)benzoate A stirred solution of methyl 5-chloro-2-nitro-benzoate (17.0 g., 0.079 mole) and the potassium salt of 2,4,6-trichlorophenol (18.6 g., 0.079 mole) in dimethyl sulfoxide (100 ml.) was heated at for 17 hours. The cooled reaction mixture was diluted with water (500 ml.) and then extracted with ether (3x100 ml.). The combined ether fractions were washed with 10% sodium hydroxide solution (2X30 ml.) and then with a saturated aqueous sodium chloride solution. The ether solution was dried (Na S0 and the solvent evaporated to give a dark oil. Two crystallizations (petroleum ether) gave 1.91 g. of a pale yellow solid, m.p. 101103.

EXAMPLE 1 LR. (Nujol): c=o 1723, c=o 1240, and 1260 cm? NMR (CDCl methyl 3.91 ppm. (3H), quartet 6.96 ppm. (1H, 1:25 and 8 c.p.s.), doublet 7.05 ppm. (1H, J=2.5 c.p.s.), broad singlet 7.05 ppm. (2H), and doublet 8.01 ppm. (1H, i=8

c.p.s.).

EXAMPLES 2 through 13 The ester of Example 1 was hydrolyzed to the corresponding acid and using known procedures for the preparation of amides, twelve other compounds within the scope of this invention were prepared. These compounds are:

(2) 2-nitro-5-(2',4-dichlorophenoxy)benzamide.

(3) N-methyl 2-nitro-5-(2,4-dichlorophenoxy)benzamide.

(4) N,N-dimethyl 2-nitro-5-(2',4-dichlorophenoxy) benzamide.

(5) N-propyl 2-nitro-5-(2',4-dichlorophenoxy) benzamide.

(6) 2-nitro-5-(2',4',6'-trichlorophenoxy)benzamide.

(7) 'N-rnethyl 2-nitro-5-(2',4,6'-trichlorophenoxy) benzamide.

(8) N,N-dimethyl 2-nitro-5-(2',4, 6'-trichlorophenoxy) benzamide.

(9) N-propyl 2-nitro-5-(2',4,6'-trichlorophenoxy) benzamide.

(10) N-isopropyl 2-nitro-5-(2',4',6'-trichlorophenoxy) benzamide.

( 1 1) N,N-diethyl 2-nitro-5- (2',4,6'-trichlorophenoxy) benzamide.

(l2) N,N-dirnethyl 2-nitro-5-(2',4'-dichloro-6-fiuorophenoxy)benzamide.

(13) N-secbutyl 2-nitro-5-(2,4'-dichloro-6'-fiuorophenoxy) benzamide.

For comparison, the following position isomer of Example 4 was prepared, the acid of which is disclosed in US. 3,475,427.

( 14) N,N-dimethyl-2-nitro-3- (2',4'-dichlorophenoxy) benzamide.

The compounds of the invention can be applied in various ways to achieve herbicidal action. They can be applied, per se, as solids or in vaporized form, but are preferably applied as the toxic components in pesticidal compositions of the compound and a carrier. The compositions can be applied, as dusts; as liquid sprays, or as gas-propelled sprays and can contain, in addition to a carrier, additives such as emulsifying agents, binding agents, gases compressed to the liquid state, odorants, stabilizers, and the like. A wide variety of liquid and solid carriers can be used. Non-limiting examples of solid carriers include talc, bentonite, diatomaceous earth, pyrophyllite, fullers earth, gypsum, flours derived from cotton seeds and nut shells, and various natural and synthetic clays having a pH not exceeding about 9.5. Non-limiting examples of liquid carriers, include water; organic solvents, such as alcohols, ketones, amides and esters; mineral oils, such as kerosene, light oils, and medium oils and vegetable oils, such as cottonseed oil.

In practice, herbicidal application is measured in terms of pounds of herbicide applied per acre. The compounds of this invention are effective herbicides when applied in herbicidal amounts, i.e., at rates between about 0.2 pounds and about 10 pounds per acre.

HERBICIDAL EFFECTIVENESS Method of Propagating Test Species Crabgrass Digitarfa sanguinalis Yellow Foxtail grass Seteria glauca development for treatment in the post-emergence phase is as follows:

Grasses: 2 inches in height Pigweed & Turnips: 1 or 2 true leaves visible above cotyledons.

Cotton: first true leaf 1 inch in length; expanded cotyledons.

Corn: 3 inches-4 inches in height.

Beans: primary leaves expanded, growing point at primary leaf node.

Method of Treatment Spray applications are made in a hood containing a movable belt and fixed spray nozzle. For passage through the spray hood, one pot of each species (pre-emergence phase) is placed on the forward half of a wooden flat and one pot of established plants (post-emergence phase) is placed on the rear half of the flat. Treatments are moved to the greenhouse after spraying. Watering during the observation period is applied only by sub-irrigation.

Compounds are screened initially at a rate of application equivalent to four to eight pounds per acre. Two weeks after treatment the preand post-emergence percent injury is visually rated. Subsequent testing was carried out at 2.1 and 0.5 pounds per acre.

Herbicidal testing of the compounds of Examples 2 through 13 and of the comparative compound showed the results set forth in Table I. The plants are tablulated using the following abbreviations:

Crabgrass CG Pigweed PW Johnson grass JG Turnip TP Barnyard grass BG Cotton CT Bean BN Corn CN TAB LE I.P RE-lPOST-E ME R GENCE 1 Bindwced.

Johnson grass Sorgum Halepense Barnyard grass Echinochloa crus-galli Amaranth pigweed Amaranthus retroflexus Turnip Brassica sp.

Cotton Gossypium hirsutum var. DPL smooth leaf Corn Zea Mays var. Golden Bantam Bean Phaseolus vulgaris var. Black Valentine All crop and weed species are planted individually in 3" plastic pots containing potting soil. Four seeds of each of corn, cotton, and snapbeans are seeded to a depth equal to the diameter of the seed. All other species are surface seeded and sprinkled with screened soil in an amount sufficient to cover the seeds. Immediately after planting, all pots are watered by sub-irrigation in greenhouse trays. Pots for the pre-emergence phase are seeded one day before treatment.

Planting dates for the post-emergence phase are varied so that all the seedlings will reach the desired stage of development simultaneously. The proper stage of seedling OzN wherein X is halogen, n is 1 to 5, and R is amido, alkyl amido (C -C or dialkylamido (C -C 2. A compound of Claim 1, wherein said compound is N-methy1 2-nitro-5-(2-',4'-dichlorophenoxy)benzamide.

3. A compound of Claim 1, wherein said compound is N,N dimethyl 2-nitro5 (2',4'-dichlorophenoxy)benzamide.

4. A compound of Claim 1, wherein said compound is N,N dimethyl 2 nitro-5-(2,4',6-trichlorophenoxy) benzamide.

5. A compound of Claim 1, wherein said compound is N,N dimethyl 2-nitro-5-(2',4'-dich1oro-6-fluor0phenoxy)benzamide.

6 6. A compound of Claim 1, wherein said compound is N-sec-butyl 2-nitro-5-(2',4'-dichloro-6'-fluorophenoxy) benzamide.

7. A compound of Claim 1, wherein said compound is 2-nitro-5-(2',4,6'-trichlorophenoxy)benzamide.

References Cited Deshpande et a1., Chem. Abst., vol. 53, col. 1400 (1959).

HARRY I. MOATZ, Primary Examiner 

1. AN HERBICIDAL COMPOUND HAVING THE FORMULA: 